1. Field of the Invention
The present invention relates to lightning protection and more particularly, preventing lightning from puncturing composite surfaces.
2. Background
External composite surfaces are susceptible to puncture when exposed to direct lightning attachment. Composite surfaces with underlying systems, such as hydraulic lines or fuel tubing, or structure require protection against the adverse effects of lightning because a puncture in the composite surface could result in a catastrophic failure, such as a spark in a fuel tank. Typically, to provide protection against lightning, metal foils or interwoven wires are added to the composite surface. Although the addition of the metal foils or interwoven wires protects against the attachment of the lightning to the underlying systems, they are heavy, difficult to apply and require special processes to prevent surface cracking due to coefficient of thermal expansion differences.
Parts of aircrafts, such as the fixed wing, wing to body fairing and empennage are being increasingly constructed of composite surfaces. It has been estimated that on average, each airplane in the U.S. commercial fleet is struck by lightning more than once each year. In fact, aircraft often trigger lightning when flying through a heavily charged region of a cloud. In these instances, the lightning flash originates at the airplane and extends away in opposite directions. To prevent catastrophic failures, a method and system are needed for preventing lightning from puncturing composite surfaces that are cost effective and add minimal parasitic weight.